The new solar cells from the University of California, Berkley use nanopillars to create cheap and efficient cells. An optimized cost could cut solar power costs to a third of current levels. (Source: Ali Javey, UC Berkeley)

New technology may unlock some massive savings

One of the biggest factors in solar power remaining an expensive power source, despite constantly improving efficiencies, is the inherent cost of materials and processing for solar cells made of polysilicon. Cutting these costs could make the solar power the preferred energy source for mankind, but thus-far there has been little high-performance designs made with cheaper processes or materials.

Now University of California, Berkeley researchers have created a new type of solar cells that may offer exactly that -- lots of solar energy with low processing and materials costs. The new type of solar cells are composed of tiny nanopillars in a thin film layer atop aluminum foil. The foil is enclosed in a protective layer of transparent, rubbery polymer.

The total materials costs are quite low, and the production costs, while not fully determined also look promising. Ali Jarvey, an electrical-engineering and computer-sciences professor who led the work, cheers, "You won't know the cost until you do this using a roll-to-roll process, but if you can do it, the cost could be 10 times less than what's used to make [crystalline] silicon panels."

The cells use a nanofilm of cadmium telluride with uniform 500-nanometer-high pillars of cadmium sulfide laid on top of it. Other thin-film solar cells with pillars have been made before, says Professor Jarvey, but they have relied on more expensive deposition techniques. Further, the new cells have an efficiency of 6 percent in transforming sunlight into electricity, where past designs had efficiencies of less than 2 percent.

Silicon-based photovoltaics still have the cell beat in efficiency with 20 percent or more in commercially available designs; however, they are extremely pure, expensive crystalline silicon. Impurities can cause electrons to get trapped in the semiconductor, so the expensive process of making this high quality crystal material is unavoidable for that design. Purity is much less of a cost concern in the new design.

Creating an equivalent amount of power would require three times the area (panels) of photovoltaic cells, given their respective efficiencies. This means that given the cost estimates, solar power costs could be cut to a third of the current levels.

Another key advantage of the new design over traditional photovoltaic panels is flexibility. Traditional crystalline panels would break if flexed. The thin film nanopillar cells, though, can be rolled and unrolled with ease.

The new design essentially divides silicon's responsibilities. The thin film material absorbs light and generates electrons, while the pillars conduct the electrons to the circuit and help to trap light. As electrons have a shorter distance to travel to reach the pillars they're less likely to get trapped by defects, and thus crystal quality is less of a concern.

Currently the cells are produced using a relatively cost-effective anodizing design to grow the pillars on a thin aluminum foil film, the bottom electrode. The thin semiconductor film is then layered over the pillars and a top electrode of copper and gold is layered thinly to complete the circuit.

Two key areas of improvement are the top film and the production process. Adopting a roll-to-roll production system could speed up the assembly and make it cheaper. Also, currently the gold only allows half the sunlight to enter the cell as its semi-opaque. Replacing the gold with a transparent material like indium oxide could double the efficiency to 12 percent or more, while not significantly impacting the cost of materials.

States Professor Yang, "(The) architecture is most important--materials we can continue working on. The beauty of this paper is the demonstration of how well the architecture works."

The research appears in this month's edition of the journal Nature Materials.

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If the cells live up to their cost potential, actually it'd a terrific deal to choose this over traditional panels.

The polymer should hold up much better than glass panelling and be more waterproof and have a longer lifetime. Further, as the article states you might only be generating a third of the power or so (6 percent versus 18-20), but you would be getting it at approximately a tenth of the cost -- that means you're ultimately getting your power at a third of the cost and could recoup your investment much faster.

If this technology lives up to its promise, it could put solar power much closer to wind and fossil fuel power. Currently the most efficient fossil fuel power cost about 3 cents per kwh, the most efficient wind power costs 5 cents per kwh, while the most efficient solar installations cost 20 cents per kwh. With this, solar could drop to as little as 6 cents per kwh, making it much more competitive with fossil fuels. The longer life could drop costs even further as well.

Unlike a lot of environmental thinkers, I don't support the solar power movement primarily based on emissions, etc. Rather, I consider it a valuable technology to develop and market as it will be one of our best bets in the near term when we're exploring and colonizing the reaches of outer space. Nuclear fusion and fission are the two other primary alternatives, depending on how much water/isotope-containing ores you have.

You actually raise an interesting point from an op-ed piece I read several years ago ... the basic premise was that the American culture of consumption (water, energy, food, etc.), personal space, modern conveniences, meticulous personal hygiene, etc. essentially preclude many Americans from participating in a space diaspora, if one is coming.

Other cultures like China, Japan, India, or even Europe are more predisposed to compromise and forgoing comfort for the greater good. You are much more likely to successfully house 500 people like that in a closed ecology biosphere.

Personal freedom at the expense of communal ideals may be the American way, but for a spacefaring society it's not tenable.

Seeing as how you can fit all the worlds people into the state of Texas, and give each family of 4 a small home, there is no shortage of space in the US. Not to mention that 10% of our entire country are national forests/parks.

Was just merely pointing out that cramming people into a small space with limits to natural resources is not necessary. I mean, if you want to live in a tin can with 500 people, be my guest, but there isn't any need for it.

No, you're just missing the point of his response. The idea tha Americans wouldn't fare well in space is a huge assumption based on the fact that we are spread out and enjoy plenty of food, water, etc, when people from other parts of the world are packed together and have fewer of those resources (whether it's true or not). His point is that the only reason people in other parts of the world live like that is because they're forced to, and we don't live that way because we are not forced to. We're all human beings, and we all do what we have to to survive, and we all will take whatever comforts we can afford.

Your point is somewhat valid, it would be an adjustment for many Americans, but I think it goes a little far. Obviously if the benefits of living in space outweigh living on Earth where you can sprawl out and eat lots of food and take long showers, then anyone would do it, regardless of where they're from. But I guess I see your point. If living in space really has no benefits and sucks like you describe, I guess Europeans might decide to live there and Americans might not.

It's a rather grey point if you ask me. Yes, America is mostly covered in forest, farm, or even uninhabited by man completely. Man however decided not to live in these areas for a reason. The decided to live in crowded metropolises closer to resources and next to the coast lines.

I just want (hopefully, although doubtfully) myself and my descendants to colonize new planets and gain the mineral rights to them so 200 years from now, two of my female descendants can marry someone named Weyland and the other can marry someone named Yutani and my future family can then use their ridiculous wealth to explore and mine other planets while keeping a keen eye out for hostile life forms to be used in urban pacification.

Leading silicon based solar cells get up to 20% (and sometimes better) efficiency. GaAs and multiple junction cells are getting into the mid 30% efficiencies (though their prices are higher than simple silicon ones).

A 6% efficiency has a long way to go. Even a jump to 12% is not that great.

While it may be feasible in certain climates to use this material as a roof covering (think of areas where hail, microbursts, etc. are very rare). I can't imagine using any solar array as a full roof covering until it becomes more "bullet proof".

Modern asphalt shingles (and even more so, tile and asphalt looking steel shingles) are quite resistant to most hazards. Besides getting the efficiencies up, these materials will have to significantly increase their physical robustness.

As for covering your southern (and maybe eastern & western) faces of your house -- I can't imagine the average homeowner covering their "lovely home" with solar cells even if it saved them $1,000 a year.

quote: I can't imagine the average homeowner covering their "lovely home" with solar cells even if it saved them $1,000 a year.

Heck no, I wouldn't cover my roof with that stuff...nor will I bow to the governments wishes of painting my entire roof white.

Obviously, those are personal preferneces. But I think the reason most people wont invest in these things are the same reason they don't feel the need to sell their current cars to buy a hybrid. The length of time your going to keep the car, factored in with the higher cost difference between the non-hybrid version, the total out of pocket costs to obtain the car, and possibly any loss you take on the current car...it just doesn't make sense to put yourself through that financial mess to save 10-15mpg's to "feel good".

Actually, even if I had a 10,000 square foot home, I'd love to cover it with extremely high efficiency solar cells. There's something about the thought of making everyone else pay for electricity that I get free from the Sun that makes me smile.

I wish some ridiculously advanced new technology could be developed in the next few years that gave the cells a near 99% efficiency and could be produced at a cost of say, $1 per square foot or so... pipe dreams for now I guess. :)

I estimate a solar roof over the same area using an aluminum base with this technology at 1/3 silicon panel prices would be about $10000 installed.

I am confident they could make this last 30 years.

So, instead of paying $880 per year for my asphalt roof and electricity...

I pay $510 per year for my metal solar roof and electricity.

Seems like a pretty good idea. I save $400 per year. If I'm really worried about hail damage, microbursts, etc. taking out the entire roof, I think I could probably get insurance coverage for under $200 per year. Still save $100 per year over long term.

quote: but you would be getting it at approximately a tenth of the cost

As long as supply is limited to patent holders and licensing, there's no way anything like this would be sold for much less than a third of the cost of current tech. It's possible applications are more versatile, it would probably last longer and be cheaper to intsall. Even though you're giving up overall efficiency, these qualities alone would let the manufacturers charge more per percentage point of efficiency.

If you have a product that is comparable to other products on the market, but ten times cheaper to manufacture, why sell it for so much less and give up all that profit? I'd sell it for half the cost of regular solar to stimulate sales, and put that 400% profit im my pocket. Capitalism is awesome isn't it?

quote: If you have a product that is comparable to other products on the market, but ten times cheaper to manufacture, why sell it for so much less and give up all that profit? I'd sell it for half the cost of regular solar to stimulate sales, and put that 400% profit im my pocket. Capitalism is awesome isn't it?

Until "King" Obama decides you are a greedy capitalist and takes over your company for the sake of saving the world.

Until fossil fuel power properly factors in the REAL cost of supplying our air, land, and water with dangerous chemicals and killing thousands of our citizens with mine collapses and black lung disease and coal ash spills, can a REAL cost analysis be conducted.

Don't mix emotion with fiscal responsibility. Haven't you watched Washington do that for decades and put us in this hole were in right now?

When looking at cost and policy, only use real statistics - don't try to put your emotional and environmental spin on it. That's irrational and competely dishonest. You act as if those people in the mines were forced there - as if they couldn't move to a different city/state and get a different job.

If you want to get emotional, why don't you go figure out what we're going to do with all the chemicals from your precious hybrid and battery operated cars.

Unfortunately the 1/10 cost factor only applies to the cells themselves. At low efficiencies and thus large collector areas the cost of the support structure, the panel supports, the installation and mounting etc start to become the dominant factors. Even if the cells themselves are free they become uneconomical to use at low efficiency because of the ancillary costs.

Perhaps if they can get the efficiencies above 10-12% they might become economically feasible, if everything else falls in their favor.

Their (physical) flexibility will reduce ancillary costs. It should also reduce maintenance and replacement costs since they can simply be rolled up in potentially damaging situations.Also makes it especially exciting for portable applications.

You missed my point. If they're only 1/3 as efficient, then I need 3x the space. A roof is only so big. And considering the amount of space a typical solar plant already takes up, do we really want to have to need 3x the space? Even if its cheaper? We need more power, not less.

I'm not against a person spending their own money to put solar on their roof. I'd do it too if I owned a home in an area where it made sense. Fact is though, in much of the country, that isn't the case. But I'm talking about large scale power plants.

No doubt. I just wanted to inject some tongue n' cheek in there. I'm very pro-nuclear.

Solar would not work where I live, it rains constantly (at least we tell the Californians that so they don't move here!). Though Seattle gets the majority of its electricity from efficient hydroelectric turbines.